hm, first test shows zoplfi being 70x slower to compress than deflate for 0.2% better compression ratio… this is likely because focus of their deflate is strong er compression for png images.

However in archiver, this would be very impractical since you can use 7z format for instance to achieve much better compression at much faster speed. For instance they show 7z at ultra setting being 20x faster than zoplfi while getting much better compression.

Similar implementations of stronger but much slower deflate existed before (kzip), and are used for various png re-compress tools.

Fair point. Zopfli is already in use for PNG re-compression.
Since it it deflate-compatible no further support is needed on PA side I understand.

But if some sort of “real” format of Brotli gets adopted at least decompression support for that could be implemented (like PA already supports some more exotic formats).

Thanks for your considerations so far

if they add it for 7z or zip, we will use it of course, but again, this seems to be made for web page compression where speed of extract is important… test shows LZMA being 8x faster at ultra than Brotli with LZMA being tested at low window sizes, which means comparing it to classic LZMA window sizes, it would get much better results.

For them though, most important part is again speed of decompression, which is only where it is likely good.

So I dont think you will see this implemented in real archivers, unless someone makes modifications that make it much better.

@spwolf Yeah it really is only for high-demand resources where you want to squeeze the smallest possible size out of it and you do not care that it takes half an hour to compress it in the first place. It’s bandwidth optimization.

Is is possible to add a “Pause” button to temporariy stop the compression? For example, just like what I am doing now, I am archiving “My Documents” with over 5GB totally. It would be a long-lasting journey for PA to finish the whole archiving process. However, I may choose to do some small tasks when PA is compressing and I may prefer to pause its action for a while.
Currently PA seems not supporting this… Would it be available in the following versions?

I’m well aware of what RPMs are for, but they are basically specialized archives which also contain file based instructions for the RPM software to use when installing the program. They can also be accessed just as a regular archive.
Several Windows-based archivers already support viewing/extracting RPMS including:
(no links to other zip software please - admin - thank you)
Edit: Just proving my point; several other archivers do support this (including freeware), it’s not some mystical technology.

Hi, today I was modifying some nVidia driver files, but they seem to have SZDD compression. PowerArchiver is not able to open this files or even extract them.
I have no further information about this compression mechanism, however I do know I can extract those archives using Microsofts Expand tool.
I would like support for this compressiontype. Also other driver packages have sometimes SZDD compression.
Here some History
CAB History
In 1977, Abraham Lempel and Jacob Ziv devised and published a paper on their new compression method, LZ77. In 1982, James Storer and Thomas Szymarski released their LZSS variant. In the early 1980s, Microsoft required some form of data compression for their installation media to cut down on the number of disks needed to install MS-DOS and Microsoft Windows, so they took Haruhiko Okumura’s implementation of LZSS. Their compressed files had a SZDD signature.
Also a link with lots of information: http://www.kyz.uklinux.net/cabextract.php

C:\>echo “This is the unnamed stream” > TestFile
C:\>echo “This is a stream called Stream1 in the same file” > TestFile:Stream1
C:\>echo “This is a stream called Stream2 in the same file” > TestFile:Stream2
C:\>dir TestFile
Volume in drive C has no label.
Volume Serial Number is 504D-8531
Directory of C:\
08/02/99 01:12a 31 TestFile
1 File(s) 31 bytes
0 Dir(s) 1,078,935,552 bytes free
C:\>more < TestFile
“This is the unnamed stream”
C:\>more < TestFile:Stream1
“This is a stream called Stream1 in the same file”
C:\>more < TestFile:Stream2
“This is a stream called Stream2 in the same file”
When i compress a file that has additional streams attached to it, and decompress it, those named streams seem to be lost
PS: ADS = Alternate Data Streams
http://support.microsoft.com/kb/105763